Electrical heating-furnace.



Nu. 677,070. Patented June 25, I90l. A. H. EDDY.

ELECTRICAL HEATING FURNACE.

(Application fllad June 15, 1900.)

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No. 677,070. PM June 25, I901;

, A. H. EDDY.

ELECTRICAL HEATING FURNACE.

A nmin filed June 15, 1900.

(No Model.) 2 Sheath-Sheet 2.

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UNITED STATES PATENT -OFFICE.

ARTHUR H. EDDY, OF WINDSOR, CONNECTICUT.

ELECTRICAL HEATl'NG-FU RNAC E.

SPECIFICATION forming part of Letters Patent No. 6'77,07 0, dated June 25, 1901.

Application filed June 15, 1900. Serial No. AM. (N0 model.)

sisting conductors.

The object of this invention is to provide a simple and efiicient furnace of this nature which is particularly adapted for the purpose of fusing refractory substances, such as enamels, upon more or less refractory bodies,

velop.

suchas pieces of clay. or metal, without heating the bodies enough to destroy their texture and without precipitating deleterious'or discoloring matter upon the fused substances.

The invention resides in a furnace having terminal clamps connected with the electrical circuit and holding highresisting electrical conductors that are enveloped in a refractory material which will prevent the disintegration of the conductors and prevent fluctuaations of the temperature.

Figure l of the accompanying drawings shows a horizontal section of a furnace that embodies the invention. Fig.2 shows a transverse section of such a furnace. Fig. 3 is a plan, on larger scale, of one of the clamps for holding the conductors and the refractory envelops for the conductors. Fig. 4 is a transverse section taken across the conductors and envelops, showing a side elevation of one of the clamps; and Fig. 5 is across-sectional view taken through the clamps and one of the highresistance conductors and its refractory en? The furnace 1 can be built any required size and any desired shape and the walls maybe made of any suitable material. Placed in openings 2 in the opposite walls of the furnace shown are the clamps 3, which hold the ends of the high-resistance conductors 4, that extend across the interior of the furnace. These clamps may be made to hold any desired number of conductors, which preferably are carbon-rods, those shown being arranged for three, four, and five carbons. Any

desired number of pairs of clamps may be employed. The circuit-wires 18 are connected with the clamps, so that the current flows in parallel through the carbonsheld by each pair of clamps, which pairs of clamps are joined in series to better enable the heat to be graded. The body of each of these clamps is hollow and is provided at each end with a nipple 5, those nipples at one end being connected with a water-supply pipe 6 and those at the other end being connected with a drainpipe 7. Any common means may be employed for forcing water through the clamps for the purpose of keeping them cool. Sections of rubber hosev 8 are employed in the circulating system to'properly insulate the clamps. g

The clamp-bodies are provided with mortises 9, in each of which is a clamping-jaw 10.

After the carbons 4 have been placed in the mortises beneath the jaws plates 12 are forced down by set-bolts 13 for causing the jaws to firmly clamp the carbons.

In, the body of the clamps, around each carbon-opening, is a socket 14, and supported by these sockets are thetubular envelops 15,

which extend from clamp to clamp across the furnace and inclose the carbons. The sockets are made sufficiently large to permit the parts to expand and contract without breaking the tubes and still keep the ends of the tubes substantially sealed. These envelops are preferably formed of round porcelain tubes having a somewhat larger interior diameter than the diameter of the carbons,.so that there will be an air-space between the carbons and the porcelains. The carbons and the porcelain tubes are circular in crosssection. Any other shape, however, could be employed. The tubular envelops may be formed of other refractory materials than porcelain.

The clamps are tapped on the outer face and provided with set-screws 16 for clamping the terminals of the circuit-wires.

Bricks, tile, china, or articles of a similar nature may be carried by any suitable means into this furnace adjacent to the refractory envelops of the conductors and subjected to the heat generated by the flow of electricity through the resisting conductors in such mannor as to fuse any enamel or material of like character which may have been applied to them either in a'solid,powder,ed, pasty, or

the orossseclm lel ar a fft ca o .912 ls a s st n inta ng'ah ven reeof temperature,as they protect the.

plastic condition. The heat emitted from the furnace is so intense and so directed that the enamel is fused without affecting the condition of thea-rticle to which the enamel is ap: plied, the article notremaining in the furnace a sufficient length of time to become heated through. The clamps may be so arrangedthat the article as it passes through the furnace may be subjected to a gradually-increasing temperature and thento a gradually-decreasing temperature in order to eife'ct the best results. Any common means may be employed for i? feeding the articles continuously through the furnace or for passing them in and withdrawhs-them the same 1Tb? employmeh h t 're abtory envelopf nr ent th i i teg at o .hft c on hh'slhh h queh pre p wt hn up n t fused enamel of the ash which would result t dis n ation, ls h ng s o 1 hhct r t-y v a w hldf ol w ad m h of li s. carbons from the cooling effect of drafts of the consequent changes in the d gree of. he r hndh i y and eat miaing ci parit th m l y ent" o he rh i FQ Y'BH IOP of h n t re. or th bons the fused enamel is protected from the ashes of the disintegrating carbon, theheatis main- I t l ie hhifhrm uhhe e i ieh yo plant is increased. ,These envelops are prefarshly fo med o po nau t y may be made of some similar clay material, and these'substances,-while non-conductorsunder normal conditions, become fair I conductors their be ng h at d o a h h gre I t ihrnace at'terthefdesired temperature has if agmihje r u tth hnv lcn th c m ngvhi .h psmdh lm-s, e ta inh eas dmnd th ampe esr duh r y fav ly ef g the eff ciency of the electrical apparatus. The

I iive ep a i a r spe ific re s than the interior cond uctors require a higher voltageto cause a proper flow of current; but reason of'this resistance asmaller amouut o t: current will produce the desired temperature, Off course the wattsare the same, ,flhe operation of thisfurnace may be continhed with thegporcelain" tubes alone, after they become sufficiently heated, by increas- Yihs he olt e of t cu n s h shmil the carbons become dissipated or disinte grated or entirely removedthework would not be'interrupted. It is even possible to dis- .pense with the carbon conductors, for by em- -ploying supplemental means for heating the porcelain non-conductors when startingup the plant they may be heated to sucli'a degree that current of high voltage may be passed through them to keep them hot, and then the supplemental means for heating may be removed. ,n.

I claim as my inv'ention- 1. In an electrical heating furnace, the com bination of higheresistance conductors, circ it-terminal clamps holding the ends of the conductors, refractory tubular envelope en tirely surrounding the conductors and held by and in electrical connection with the clamps;

and an air-space between the oonductorsand the envelops, substantially as specified.

2 Inan'electrical heating-furnace, thecombination of high-resistance conductors3cir cuit-terminaliclamps holding the 'endsj of the conductors, refractory tubular envelops. en-

tirely surrounding the cond ucto rsand heldsby and in electrical connection with the clamps, an air-space betweenthecon'ductors and the ,envelo'ps, and means for keeping theclamps 0 s bstan ially as specifi d- 3, An electricalheating-furnacehaving exterior walls, circuit-terminal; clamps located in the walls, high-resistance cond ucto'rs'held by, and in electrical. connection with. the

clamps; refractoryftubularenvelops which when cold'are insulators but when in use become conductors, thetubular envelops ent rely surr n ng t flh pma e v f th v coriductorgandjheld by and inblectricalconnection; with the clamps, substantially as specified. I l V l I M At. An electrical, heating-f urn ace hav'ing'exteriorwalls, hollow clamps connected with the circuit-wires, fluid-circulation pipes connect, ed with the clamps for keeping the clamps cool, high-resistanceconductors held bythe clamps, tubular bodies which are good electrical non conductors when cold and electrical;

conductors when heated to a high degree,entirely surrounding and, separated from the high-resistance'conductors, extending across thein'terior of the furnace, and held by and in electrical connectionwith theclainps, and.

means for raising the temperature of the condoctors and tubular bodies andtransforming 1 the tubular bodies from non-conductorsto con ductors of electricity, substantially as specified.

Witnesses: I HARRY R. WILLIAMS, (LE. BUoKLAND.

IIO.

ARTHUR n. EDDY. 

